1. Field of the Invention
The present invention relates to a keypad and, more specifically, to a brief numerical keypad, which simplifies the number of keys and their arrangement.
2. Description of the Related Art
FIG. 1 shows the arrangement of a conventional numerical keypad. As illustrated, the numerical keypad comprises 10 keys ranged from “0”˜“9”. The keys “1”˜“9” are arranged in the form of a 3×3 matrix, and the key “0” is independently disposed near the matrix. Each key has a top operation face printed with a numeral or a sign expressing a specific number, a bottom mounting face provided with signal transmission means corresponding to a respective contact at a keypad matrix circuit. When pressed one key, the corresponding contact is electrically connected, thereby causing the keypad matrix circuit to output a corresponding scan signal.
In order to let the operator accurately press every key without trigging neighbor keys, the keys are orthopedically engineered to have an about 12 mm×12 mm operation face, and spaced from one another at a pitch not less than 5 mm. However, the size of a numerical keypad must be reduced when used in a compact, small-sized electronic apparatus. When a numerical keypad made in a mini form, the operator may click a wrong key or erroneously click two keys at the same time. Further, if the operator suffers an eyesight problem, he (she) may be unable to identify the keys of a mini numerical keypad.